Global Veterinaria 6 (4): 417-423, 2011
ISSN 1992-6197
© IDOSI Publications, 2011
Computed Tomographic Anatomy of the
Fore Foot in One-Humped Camel (Camelus dromedrus)
Adel M. Badawy
Department of Surgery, Anaesthesiology and Radiology,
Faculty of Veterinary Medicine (Moshtohor), Benha University, Qalubia, Egypt
Abstract: The purposes of this study was to describe and identify , the complex anatomical structures of digits
and foot pad of the fore limb in one-humped camel by using the computed tomography scan (CT scan) and
gross anatomy, which would be used in diagnosis of foot and footpad disorders. The study was performed
on three pairs of camel's fore feet. Transverse and sagital CT images were obtained by using Hitachi-CXR
4Multi-Slice CT Scanner. The different anatomical structures of the digits and footpad were identified in the
frozen sections, the fixed slices and the dissected specimens. The CT images were compared with the
corresponding sections at the same levels and selected for their identity and photographed. The analogous
anatomical structures were identified on the transverse and sagital slices and labeled with the corresponding
structures on the CT images. Results revealed that, the frontal tip of each digit was covered by a characteristic
small nail. The distal and middle phalanges were horizontally situated, while the proximal phalanx obliquely
positioned. Their planter surfaces were separated from the ground by foot pad. Three digital cushions enclosed
in a common capsule were found underneath each digit. On CT images, the inner structures of the foot and foot
pad were appeared with various gray scales. It was concluded that, camel has unique feet morphological
peculiarities. CT was efficient imaging modality that provides a cross-sectional image with superior soft tissue
differentiation and no superimposition of the overlying structures, which can be used for better diagnosis of
foot and foot pad abnormalities.
Key words: Camel
CT scan Cross-section
Digits
INTRODUCTION
Footpad
value to evaluation of soft tissue, although
ultrasonography provides visualization of tendons and
ligaments [8-10]. Alongside, ultrasonography provides
a small view and each structure has to be separately
imaged and a cross sectional examination through the
entire digit is not possible. On the other hand, soft
tissue is difficult to be evaluated by ultrasonography
in the digit [11]. CT, through its high spatial resolution
and moderate differentiation of tissue contrast is a
fastened exceptionally useful technique for visualizing
general anatomy [12].
The use of CT in large animal medicine is currently
limited by logistical problems of acquiring CT images;
meanwhile a few CT studies on horse's foot have been
done [13]. Computed tomography (CT) is anatomic crosssectional imaging that uses x-rays and x-ray attenuation
to create the images [14, 15]. The CT gantry houses a row
of x-rays detectors across from an x-ray generator.
Camels are a fascinating and little studied animals.
Camel is a unique among artiodactyls in their regular
employment of pacing gait and having a unique foot
morphology assumed to be an adaptation for this mode of
locomotion [1-3]. The uniquely designed wide spread feet
enable him to walk on shifting sand in the desert and
rough rocky terrain whereas the footpad is used to grip
onto rock and steep inclines. Their feet are secondarily
digitigrade, with a splayed -toed foot, loss of hooves,
addition of a broad foot pad and loss of the interdigital
ligaments, allowing the divergence of the third and
fourth digits [3-5]. Imaging techniques play a major
role in the modern biomedical research [6,7]. Current
diagnostic imaging techniques such as radiography and
ultrasonography provide limited information for
evaluation of the camel foot. Radiography has limited
Corresponding Author: Adel M. Badawy, Department of Surgery,Radiology and Anaesthesiology,
Faculty of Veterinary Medicine Benha Univeisity, Qalubia, Egypt.
Tel: +202-42132555, Mob: +2011-8859378, E-mail: [email protected].
417
Global Veterinaria, 6 (4): 417-423, 2011
The gantry rotates around the region of interest on
the patient creating a "cross-section x-ray image" in
sequences of slices. The basic physics of CT are
dependent on tissue density, similar to planar radiology,
but
CT's
cross-sectional
nature
eliminates
superimposition of structures and dramatically improves
resolution. C.T imaging is particularly useful in the skull,
thorax, abdomen and limbs. C.T image interpretation is
based on the principles of radiology, as it made of black
color, white and shades of gray (called gray scale),
assigned to tiny squares (pixels) arranged in columns and
rows( a matrix) and can record thousands of opacities
ranging from air to high density metal images [16].
Accurate interpretation of ultrasonography or CT of the
foot requires a thorough knowledge of the cross sectional
anatomy of the region and accurate interpretation of the
plan metric CT is necessary for the study and evaluation
of the pathological condition or damaged tissues [9, 17].
The objective of this study was to describe the
cross-sectional
anatomy
compared
with
the
corresponding CT images of the digits and foot pad in
one-humped camel, which provides data, would be used
for evaluation and diagnosis of foot and foot pad
abnormalities.
transverse and sagital slices and labeled with the
analogous structures on the corresponding CT images.
RESULTS
One hundered and thirty CT images were obtained
for fore feet of one-humped camel (Cameleus
dromadrius). Twenty cross and Ten sagital sections
photographed and matched with their identical
corresponding CT images were selected and labeled. The
transverse CT images provided excellent depiction and
details of anatomical structures when compared to their
identical photography. Dorsoplanter plans were not
expressive for the relations of the anatomical structures
of the digits or the foot pad (Fig. 1). Particularly,
identifiable anatomical structures were labeled on the
sections with their analogous corresponding CT images.
Sections with bilateral symmetrical structures were labeled
only on one side. Bones were the densest tissue on CT
of the foot and appeared as the whitest hyperdense
tissue, with a well-defined dark shaded medulla, similar to
their appearance on radiographs. Superficial and deep
digital tendons and their fibrocartilagenous enlargements,
ligaments and foot pad were appeared on various gray
scales on CT images. On CT images Synovial fluid, joint
cavity and blood vessels were well-defined radiolucent
(hypodense) smoothly margined.
The sole of the fore foot of the one-humped camel
was characterized by its round shape with short
interdigital cleft (notch) between the third and fourth
digits (Fig. 3). Dorsally, the frontal tip of each digit had a
characteristic small nail instead of skin appeared as
hyperdense well-defined on CT images (Fig. 2). The
nail measures about 5-6cm dorsoplanter and 4-5cm
transversally. The inner structures of fore feet were
included; the distal phalanx (3rd Phalanx) and middle
phalanx are nearly horizontally situated (position) and the
proximal phalanx (1st phalanx) was obliquely positioned
(Fig. 2). The planter surfaces of the distal and middle
phalanges as well as the distal half of the proximal phalanx
of both digits were separated from the ground by the
layers termed together foot pad (Fig. 2).
Proximodistally, they were, the sole, its epidermal
layer, common capsule (layer of connective tissue fascia)
covering three digital cushions for each digit and
planterly the yellow fibroelastic bed, which separated
from those of the other digit by a thick highly vascular
interdigital septum (Fig. 4). The digital cushions were
included, axial, middle and abaxial cushions. CT images
were providing good contrast between these structures.
MATERIALS AND METHODS
Three pairs of fore limbs of the camel (Cameleus
Dromadrius) were used in this study; they had been
obtained from the slaughter house of Toukh, Qalubia
governorate, Egypt. Limbs were sectioned 10 cm above
the level of the fetlock joint. Computed tomography was
performed at 130 kiolvolt and 80 mA by using HitachiCXR 4Multi-Slice CT Scanar. Continuous transeverse and
sagital series of CT scan were obtained every 1 cm
thickness from one pair of the fore feet. The images were
printed by using Hitachi-digital printer and photographed.
Another pair of fore feet was frozen at-15°C and
sectioned in transverse and sagital plans in slices of 1 cm
thickness with high speed electric band saw and
photographed. The frozen sections were fixed in formalin
10% for further anatomic investigations. The remaining
pair of feet was dissected freshly for further identification
of the anatomic structures, photographed and fixed in 10
% formalin. The different anatomical structures were
identified in the frozen sections and the fixed slices with
the aid of the available references [2-5]. The CT images
were matched with the corresponding sections at the
same levels and plans and selected for their identity. The
relevant anatomical structures were identified on the
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Global Veterinaria, 6 (4): 417-423, 2011
(A)
(B)
Fig. 1: (A) Dorsoplanter CT image and (B) Dorsal view of dissected foot. 1, metacarpal bone ;2, divided metacarpal bone;
3, fetlock joint; 4, proximal sesamoid bones; 5, proximal phalanx; 6, pastern joint; 7, middle phalanx; 8, distal
phalanx; 9, sole; 10,nail or pes; 11, interdigital notch; 12, interdigital septum; a, tendon of muscle extensor
digitorum lateralis; b and c , medial and lateral tendons of muscle extensor communis; d, true common extensor
tendon ; e, proper extensor tendon of the third digit ; f, proper extensor tendon of the fourth digit.
(A)
(B)
Fig. 2: (A) Sagital CT image and (B) cross section at the level of the middle of the nail. 1, distal exterimity of the
metacarpal bone ;2, proximal phalanx; 3, middle phalanx ;4, distal phalanx; 5, proximal sesamoid bone; 6, deep
digital flexure tendon; 7, fibrocartilagenous enlargement of the deep digital flexure tendon; 8, middle scutum;
9,yellow bed; 10, digital cushion; 11, common capsule of the digital cushions; 12 epidermal layer of the sole; 13
sole pad; 14, distal scutum;,N, nail.
(A)
(B)
Fig. 3: (A) Transverse CT image and (B) cross section at the level of the sole pad, showing some what round sole and
interdigital notch.
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Global Veterinaria, 6 (4): 417-423, 2011
(A)
(B)
Fig. 4: (A) Transverse CT image and (B) cross section at the level of middle of the nail. 1, nail or pes; 2, distal phalanx;
3, middle phalanx; 4, abaxial digital cushion; 5, middle digital cushion; 6, axial digital cushion; 7, epidermal layer
of the sole ; 8, sole pad; 9, interdigital notch; 10, coffin joint.
(A)
(B)
Fig. 5: (A) Transverse CT image and (B) cross section at the level of nail connection with the skin. 1, nail or pes; 2,
middle phalanx; 3, fibrocartilagenous enlargement of the deep digital flexure tendon; 4, yellow fibroelastic bed
highly vascular interdigital septum
(A)
(B)
Fig. 6: (A) Transverse CT image and (B) cross section at the level of pastern joint. 1, proximal extremity of the middle
phalanx; 2, distal extremity of the proximal phalanx; 3, middle scutum; 4, fibrocrtilagenous enlargement of the deep
digital flexure tendon; 5, yellow fibro-elastic bed; 6, highly vascular interdigital space; 7, pastern joint.
(A)
(B)
Fig. 7: (A) Transverse CT image and (B) cross section at the level of fetlock joint.1, the articular surface of the proximal
extremity of the proximal phalanx; 2, proximal sesamoid bones; 3, deep digital flexure tendon enclosed in; 4,
superficial flexure tendon.
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Global Veterinaria, 6 (4): 417-423, 2011
(A)
(B)
Fig. 8: (A) Transverse CT image and (B) cross section at the level of proximal sesamoid bone .1, distal extremity of the
metacarpal bone ; 2, proximal sesamoid bones; 3, deep digital flexure tendon enclosed in; 4, superficial flexure
tendon.
Fig. 9: Dissected planter aspect of the camel fore foot and
foot pad (sole removed). 1, superficial flexure
tendon split to pass ; 2, deep digital flexure
tendon; 3, axial digital cushion; 4, middle digital
cushion; 5, abaxial digital cuhion; 6, middle fibrous
septum of the common capsule; 7, outer part of the
common capsule; 8, fibrous connective tissue
septa between digital cushions; 9, epidermal layer
of the sole pad; 10 sole pad; 11, interdigital notch.
Fig. 10: Dissected planter aspect of the camel fore foot. 1,
DDFT; 2, upper fibrocartilagenous enlargement
of the (DDFT); 3, proximal scutum; 4, middle
fibrocartlagenous enlargement and underneath it
middle scutum; 5, insertion of the DDFT in the
distal phalanx; 6 and 7, SDFT
The superficial digital flexure tendon (SDFT) were
bifurcated distal to the middle of the metacarpal and split
below the fetlock joint to allow for passage of the deep
digital flexure tendon (DDFT) and inserted in the
proximal aspect of the 2nd phalanx by means of the
fibrocartilagenous middle scutum. Deep digital flexure
tendon was passed between the interosseus medius and
superficial digital flexure tendon (Figs. 5-10). At the level
of the distal third of the metacarpus it splits, each branch
run over the palmar ligament of the proximal sesamoid,
pierce the bifurcation of the superficial digital flexure
tendon and run over the middle scutum whereas it is
enlarged and thickened by fibrocartilage. The tendon
fattened and inserted on the flexure surface of the distal
phalanx. There were no evident for the presence of distal
sesamoid bones in dissected sections or on the CT
images.
DISCUSSION
The data presented in this study would serve as an
initial reference for the evaluation of CT imaging
diagnosis of the one-humped camel foot and foot pad
disorders and understanding the complex anatomy of the
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Global Veterinaria, 6 (4): 417-423, 2011
Raji et al. [9], Baptsite et al. [24] whose mentioned that
bone and hard tissues appear radio-opaque(hyperdense)
on CT images. The deep digital flexure tendon was
enclosed by the superficial digital flexure tendon, which
appeared with mixed contrast. In the present
investigation, it was observed that, in the dissected frozen
sections the digital cushions were three fibroelastic soft
structures, this confirmed on their analogous CT images
where they observed as three slight radiolucent
(hypodense) structures rested on more denser sole pad,
similar anatomical findings were reported by Smuts and
Bezuidenhout [2] Karkoura [4] and Shawki et al. [25]. The
foot cushion might be serve to absorb mechanical shock,
store and return elastic strain energy, protect against local
stress and keep pressure low and exhibit similarities to the
feet of humans , rhinoceroses and elephants [26]. On CT
images the joints and the digital blood vessels were
represented the exact radiolucent (hypodense) structures
having the least density, these might be attributed to their
contents are fluids [9, 27].
foot and foot pad in camel. Radiology is a very useful
tool and is often the first ancillary imaging test used when
a pathological condition of the foot is suspected [18]. It is
a planar imaging modality whereas a three-dimensional
structure is projected onto two dimensional image results
in superimposition of many anatomic structures, which
can obscure or confuse important radiographic findings.
In general, radiology has significant limitations in
evaluation of soft tissues this in a line with that
mentioned by Dixon and Dacre [15] and Weller and Taylor
[19]. Computed tomography scan is excellent imaging
modality. Its usage in veterinary medicine is, however,
limited as it is expensive and the animal should be
anaesthetized [9, 20]. Nevertheless, it has some potential
advantages over the routine radiography; it provides a
cross-sectional image with superior soft tissue
differentiation and no superimposition of the overlying
structures, which can be used for better diagnosis of
abnormalities and for evaluating the extent and severity of
the lesion , this similar to that reported by Walker et al
[21]. Between four diagnostic imaging techniques such as
radiography, ultrasonography, CT scan, magnetic
resonance image (MRI), ultrasonography is most powerful
and readily available tool providing cross-sectional
imaging with high quality, high frequency system
particularly for imaging of digits, but there are many major
limitations associated with ultrasonography that make it
an unsatisfactory method for the study of the crosssectional anatomy [9]. The diagnostic ability of the
ultrasound is highly operator dependent and that in-depth
knowledge of the topographical anatomy is of paramount
importance in making accurate diagnosis, in addition to,
individual ultrasound images represent only apportion of
the complete cross-sectional anatomy [22]. Furthermore,
the ultrasound is unable to penetrate bone and structures
containing minerals [19,23]. Normal CT image is necessary
for identifying anatomical structure of the animal. The
present study demonstrates that CT scanning have
considerable advantages over the other diagnostic
imaging techniques to describe and investigate the detail
of the anatomical structures of the camel foot and foot
pad. The transverse and sagital sections with their
identical CT images were provided more excellent
depictions of the anatomical structures of the digits and
footpad in camel, while the dorsoplanter plane was not
descriptive; this is attributed to the relatively horizontal
position of the distal and middle phalanx. In our study,
frozen anatomical sections with their analogous CT
images revealed that, the nail and proximal,
middle and distal phalanges and sesamoid bones were
hyperdense on CT images, this is in agreement with
CONCLUSION
In conclusion, camel has unique foot morphology
among artiodactyls. CT is excellent imaging modality that
provides a cross-sectional image with superior soft tissue
differentiation and no superimposition of the overlying
structures, which can be used for better diagnosis of foot
abnormalities.
ACKNOWLEDGMENT
I would like to thank Prof. Dr. Said M.S. Ammar,
Professor of Anatomy and Embryology, Fac. Vet. Med.,
Zagazig University, Egypt, for his valuable advices during
preparation of this work.
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